On 04/26/2012 07:42 PM, Raimo Toivio wrote:
> But, when filling very last few litres, I have to do it very
> slowly.
I had the same problem. I could never fill the tank at normal tanking
speed. The last 10 liters where a pain, but also at the beginning I
could not squeeze the tank nozzle all the way, always had to be carefull
with tanking or the filler tube would overflow.
Now I had enough of it.
Somebody (I forgot who, but I'm very thankful) mentioned that increasing
the size of the breather hose would help.
So, I took out the 3mm hose and replaced it by a 16mm tube! And routed
it into to the top of the cobra. It is only a short piece of tube, and
it runs parallel to the filler hose. I had to bore out the plug that
goes into the tank, and I also replaced the breather tube inside the
tank with a 16mm tube.
The result is great! I test-tanked today at the local gas-station, and I
could fill the tank at full speed, al the way up to the top of the
filler tube. When the tanking nozzle finally kicked off, the tank
(including the filler tube) was indeed full. No spilling, no burbling,
the tank is like a black hole until it has completely filled up.
I can highly recommend this modification. Easy to do, and very
satisfying if you have been plagued by the slow tanking syndrome.
Maybe 16mm is a little bit overdone, but this is what I had at hand. And
remember, it doesn't run to the outside, but to the top of the cobra. If
anything burbles out, it will just fall back into the tank.
>From the top of the cobra another hose runs to a breather tube at the
bottom of the airplane. This tube is 3mm (or 1/4"). This tube plays no
role during tanking, but only when the fuel cap is closed to keep the
pressure inside the tank equal to the atmospheric pressure (and to make
up for the consumed fuel).
Frans
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